1. Field of the Invention
The present invention generally relates to an apparatus for cleaning enrober heads used for coating articles with chocolate or other similar masses. In particular, the present invention relates to an apparatus for cleaning an enrober head without removing the chocolate or other similar mass from the base of the enrober.
2. Related Background Art
A coating or enrobing apparatus, that is, an enrober, is typically used to coat articles with a coating mass, such as chocolate, frosting, caramel, and other coating masses having similar rheological properties. A typical enrober comprises a continuous, driven grating conveyor belt that transports articles to be coated through the enrober, a coating station from which a coating mass is deposited onto articles on the grating belt, a drive mechanism for the belt, a heated tub positioned under the grating belt in the base of the enrober, a pump mechanism for pumping a heated coating mass from the tub to the coating station, and a blower to blow off any excess coating mass from coated articles. During the coating or enrobing process, a coating mass is released from the coating station, and falls freely onto articles on the belt. Any excess coating mass falls into the heated tub after passing through the grating belt and through or over other parts of the enrober mechanism. As a result, most of the elements of the enrober usually become coated with the coating mass.
When a coating mass in the enrober is changed to one of a different type, any of the first coating mass on any of the elements of the enrober mechanism must be removed to prevent contamination of the new and different coating mass. This removal process is typically accomplished by heating the enrober, and pumping out any coating mass remaining in the tub. Once the remains of the first coating mass are removed from the enrober, those elements of the enrober that were in contact with the coating mass must be cleaned.
Mechanical removal, such as with special cleaning tools, is difficult and time consuming, requiring access to every element of the enrober that contacts the coating mass. As a result, a second cleaning step is often required, in which hot water or a fatty material, such as cocoa butter or an edible oil, is used as a cleaning medium. When a fatty material is used in such a second cleaning step, the cleaning medium is first introduced into the tub of the emptied enrober, and the enrober is then operated without any articles on the belt, so that the cleaning medium is continuously circulated through the mechanism. As the cleaning medium follows the path of a coating mass through the enrober, it contacts all elements contacted by the old coating mass. As a result, the remaining old coating mass is melted off those elements. The cleaning medium is then removed, and the enrober is refilled with a fresh coating mass.
Where hot water is used, it is typically sprayed under high pressure onto all of the elements of the enrober, so that the temperature and pressure of the water removes any coating mass contacted by the water. As this method is basically mechanical, only those elements of the enrober directly accessible to the pressurized water can be properly cleaned. Moreover, the temperature of the pressurized water decreases rapidly when sprayed. As a result, elements of the enrober may not be sufficiently heated, so that little or no melting of the coating mass occurs on those elements not directly accessible to the sprayed water. Also, due to the high velocity of the pressurized water spray, material washed from accessible elements is often deposited onto less accessible elements in the enrober.
Certain attempts have been made to remedy these drawbacks in prior apparatus. For example, U.S. Pat. No. 5,437,723 to Sollich discloses a coating apparatus, comprising a grating belt having upper and lower runs and a tensioning device for the belt. The tensioning device has a relaxed position, which allows the upper run of the belt to be lifted away, thereby providing improved access to other elements of the apparatus for cleaning.
U.S. Pat. No. 6,348,105 to Heyde et al. discloses a method for cleaning chocolate from a coating apparatus with hot water. The method comprises filling the tub of the coating apparatus with hot water, pumping the water out of the tub with at least one pump, and directing the water, which is not pressurized, over the belt and elements of the coating apparatus. Using the tub, the water is maintained at a temperature higher than the melting temperature of the coating mass to be cleaned from the elements of the coating apparatus.
Known prior art methods for cleaning enrobers require emptying the enrober tub to clean the enrober head. Therefore, a need still exists for a method and apparatus for cleaning enrober heads that eliminate the need to empty the enrober tub. The present invention provides such a method and apparatus.